We employed the chiral unitarity approach to investigate the decay process ${\mathrm{\Xi }}_c^{+}\to {\mathrm{\Sigma }}^{+}{K}^{+}{K}^{-}$, by considering that the low lying nucleon resonance $\mathrm{\Xi }(1/2^{-})$ and the low lying scalar meson $f_0(980)$ and $a_0(980)$ that could be dynamically generated through the $S$-wave pseudoscalar meson-octet baryon and the $S$-wave pseudoscalar-meson–pseudoscalar-meson interactions, respectively. In the invariant mass distributions of ${\mathrm{\Sigma }}^{+}{K}^{-}$ and $K^{+}{K}^{-}$, we observe a distinct peak structure associated with the resonant state $\mathrm{\Xi }(1/2^{-})$ and a bit enhancement near the $K^{+}{K}^{-}$ threshold that is corresponding to the mesons $f_0(980)$ and $a_0(980)$, respectively. Consequently, we recommend more precise experimental measurements of this process in the future.

The flavor oscillations in the neutrino system are known to be related to the multimode entanglement of a single particle state. Neutrino oscillations are shown to encompass not only quantum superposition among different mass eigenstates but also a single-particle multimode entanglement in the flavor basis as they propagate. In the framework of three flavor neutrino oscillations, we demonstrate that the measures of entanglement can be expressed in terms of experimentally accessible appearance and disappearance probabilities. We explicitly show here that the genuine tripartite entanglement measure, i.e., the tangle, vanishes identically for all flavors, signifying that a three flavor neutrino system forms a W-type entangled state. Further, we investigate alternative measures of tripartite entanglement like the partial tangle and the concurrence fill, which capture the total sharing of entanglement beyond pairwise correlations. In terms of bipartite and bipartitioned entanglement measures, we derive the symmetric invariant and the concurrence fill, which quantify the distributed entanglement and are completely expressible in terms of flavor transition probabilities. These entanglement measures display distinct energy dependent patterns across the oscillation window, which can be experimentally accessible in the long baseline experiments like DUNE, providing an alternative quantum information perspective on flavor evolution. We use General Long Baseline Experiment Simulator simulations within the DUNE setup to investigate these tripartite entanglement measures in terms of neutrino energy and the length of the baseline. It is observed that, at the point of maximal mixing, these measures show near maximal entanglement between the muon and the tau flavor modes, establishing entanglement monogamy. Within the DUNE setup, the wide band of energy and expected higher sensitivity to $CP$ violation at the second oscillation maximum provide a unique advantage to explore the quantum correlation effects across a broader energy window. Thus, the flavor coherence and $CP$-phase dependent interference can influence the quantum entanglement measures among neutrino flavor modes, and thereby, such potential new physics effects can be probed in current or future planned neutrino experiments.

Sub-GeV light dark matter often requires new light mediators, such as a dark $Z$ boson in the $L_{\mu }-L_{\tau }$ gauge theory. We study the search potential for such a $Z^{\prime }$ boson via the process $\mu e^{-}\to \mu e^{-}X$, with $X$ decaying invisibly, in a muon on-target experiment using a high-intensity 1–10 GeV muon beam from facilities such as HIAF-HIRIBL. Events are identified by the scattered muon and electron from the target using the silicon strip detectors in a single-station telescope system. Backgrounds are suppressed through a trained boosted decision tree classifier, and activity in downstream subdetectors remains low. We find that this approach can probe a $Z^{\prime }$ in the 10 MeV mass range with improved sensitivity.

The short-baseline near detector (SBND), the near detector in the short-baseline neutrino program at Fermi National Accelerator Laboratory, is located just 110 m from the booster neutrino beam target. Thanks to this close proximity, relative to its $4\mathrm{m}\times 4\mathrm{m}$ front face, neutrinos enter SBND over a range of angles from 0° to approximately 1.6°, enabling the detector to sample variations in the neutrino flux as a function of the angle—a technique known as precision reaction-independent spectrum measurement (PRISM), referred to here as SBND-PRISM. In this paper, we show how muon- and electron-neutrino fluxes vary as a function of the neutrino beam axis angle and how this can be exploited to expand the physics potential of SBND. We make use of a model that predicts an angle-dependent electron-neutrino excess signal to illustrate this effect, such as ${\nu }_{\mu }\to {\nu }_e$ oscillations. We present how SBND-PRISM provides a method to add robustness against uncertainties in cross-section modeling and, more generally, uncertainties that do not depend on the spatial position of neutrino interaction inside the detector. The fluxes, along with their associated covariance matrices, are made publicly available with this publication.

We investigate the tidal response of general five-dimensional (5D) black holes in nontrivial setting of $\mathcal{N}=2$ supergravity with three vector multiplets known as STU theory, which include as special cases important solutions such as the Myers-Perry, Breckenridge-Myers-Peet-Vafa, 5D Reissner-Nordström, Kerr-Newman, and dyonic black holes. Solutions are paramterized by their mass, two angular momenta, and up to three U(1) charges. Love numbers and dissipation coefficients are obtained in the static and dynamic cases. In the latter scenario, we find new, nontrivial conditions, realized in important limiting cases of the theory, such as the Bogomol’nyi-Prasad-Sommerfield limit, where frequency-independent vanishing conditions are obtained. We also develop a ladder formalism for static solutions and derive the conserved charges. To the best of our knowledge, this formalism had not been previously derived for 5D black holes, including neutral ones. Finally, we show the emergence of Love symmetry in the near-zone regime and derive the generators of the associated $sl(2,\mathbb{R})$ algebra. It is shown that all conditions for Love-number vanishing can be explained by this algebra in terms of the highest-weight property.

The reionization optical depth ${\tau }_{\mathrm{reio}}$ has interesting connections to existing cosmological anomalies. As first studied in the context of the Hubble tension in our previous paper, a larger ${\tau }_{\mathrm{reio}}$, which could be achieved by removing the Planck low-$\ell$ polarization data, could boost $H_0$ slightly, resulting in a mild reduction of the tension between the early- and late-Universe determinations of $H_0$. It has been shown later that a larger ${\tau }_{\mathrm{reio}}$ could also relieve other anomalies including: the tension between baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) data, the neutrino mass tension, and the latest Dark Energy Spectroscopic Instrument plus supernovae data’s tension with the standard cosmological constant scenario. In this paper, we systematically analyze the correlations between ${\tau }_{\mathrm{reio}}$ and relevant cosmological parameters in the existing cosmic observation anomalies. In addition to Pearson correlation coefficients extracted directly from the covariance matrix, we also study partial correlation coefficients which measure intrinsic relationships between pairs of parameters removing the influence of other parameters. Introducing these methods of partial correlations to cosmology, we show that ${\tau }_{\mathrm{reio}}$ has weak intrinsic correlations with the parameters responsible for the tensions and anomalies discussed. The large direct Pearson correlations that allow larger ${\tau }_{\mathrm{reio}}$ inferences to alleviate the cosmological tensions each arise from complicated networks through multiple parameters. As a result, the relationships between ${\tau }_{\mathrm{reio}}$ and each anomaly are not independent of other parameters. We also introduce causal inference methods to cosmological data analyses, computing correlations to clarify the impact of large scale polarization data and the effects of CMB observations from the Atacama Cosmology Telescope and the South Pole Telescope.

Millisecond pulsars (MSPs) are observed to emit multiwavelength radiation, from radio to GeV. Spider MSPs, which interact with their low-mass companion in close orbit (orbital periods $<1\mathrm{day}$), may lead to strong intrabinary shocks that can further accelerate electron and positron pairs produced in the magnetosphere, possibly emitting very-high-energy (0.1–100 TeV; VHE) photons through inverse Compton scattering. Using 2565 days of HAWC Pass 5 data, we search for VHE emission from spider MSPs and present upper limits on individual sources. We also perform a stacking analysis to examine whether the two sets of spider systems, classified as redbacks and black widows depending on the companion mass, exhibit different spectral properties. Our study places constraints on TeV emission from MSPs and suggests that they are unlikely to contribute significantly to the Galactic diffuse emission at TeV and higher energies.

We investigate the thermal evolution of quark stars with and without a hadronic crust using an equation of state derived from perturbative QCD that incorporates the running of the strong coupling and the strange quark mass. Our analysis reveals that bare quark stars cool too rapidly to match the luminosity data, including those of the coldest observed isolated neutron stars, even when the uncertainty from the renormalization scale is taken into account. In contrast, configurations featuring a hadronic crust exhibit slower cooling and improved agreement with observational data. We also observe that the cooling band for bare quark stars narrows significantly after $t\sim 1\mathrm{year}$, whereas the configurations with a crust exhibit a larger uncertainty throughout their time evolution.

We introduce the morph approximation, a class of product approximations of probability densities that selects low-order disjoint parameter blocks by maximizing the sum of their total correlations. We use the posterior approximation via morph as the importance distribution in optimal bridge sampling. We denote this procedure by $\mathsf{MorphZ}$, which serves as a postprocessing estimator of the marginal likelihood. The MorphZ estimator requires only posterior samples, and is fully agnostic regarding the choice of sampler. We evaluate MorphZ ’s performance across statistical benchmarks, pulsar timing array models, compact binary coalescence gravitational wave (GW) simulations, and the GW150914 event. Across these applications, spanning low to high dimensionalities, $\mathsf{MorphZ}$ yields accurate evidence estimates at substantially reduced computational cost relative to standard approaches. We have found that when these approaches fail to provide accurate estimates, $\mathsf{MorphZ}$ has proven to either resolve the estimation failure or significantly improve the results. Its bridge sampling relative error diagnostic provides conservative uncertainty estimates. Because $\mathsf{MorphZ}$ operates directly on posterior draws, it complements exploration-oriented samplers by enabling fast and reliable evidence estimation, while it can be seamlessly integrated into existing inference work flows.

We propose a novel chaos indicator—time-reversed Shannon entropy (TRSE)—that leverages the interplay between time-reversal symmetry breaking and information entropy in curved spacetimes. By quantifying statistical discrepancies between forward and backward temporal evolution of particle orbits, TRSE robustly distinguishes chaotic from regular dynamics in nonintegrable systems. In contrast, integrable systems exhibit stable, symmetric probability distributions preserved by conserved quantities such as the Carter constant. We validate the method through high-precision numerical simulations in both Kerr and Schwarzschild-Melvin black hole geometries, evolving trajectories forward and backward in time. Furthermore, we refine our previously introduced particle-pair mutual information (MIPP) and perform comprehensive parameter-space scans, revealing a strong quantitative agreement between MIPP and TRSE. The two indicators emerge as complementary probes of chaos: TRSE captures symmetry breaking in orbital evolution, while MIPP measures statistical correlations. Together, they establish a unified framework for diagnosing chaos in general relativistic systems, paving a new path to understand the fundamental nature of chaos in nonintegrable systems.

In this paper, we address the normal mode analysis of the linearized Boltzmann equation for massive particles in the relaxation time approximation. We find that the sound channel and the heat channel are coupled in the massive case, which contrasts with their decoupling in the massless relaxation time approximation. In the limit of zero mass, our results smoothly reduce to the known case where the two channels decouple. By utilizing the argument principle in complex analysis, we determine the existence condition for collective modes and find the onset transition behavior of collective modes previously observed in massless systems. We numerically determine the critical wave number ${\kappa }_c$ for the existence of each mode under various values of the scaled mass. Within the range of scaled masses considered, the critical wave numbers for the heat and shear channels increase with increasing scaled mass, while that of the sound channel exhibits a nonmonotonic dependence on the scaled mass. In addition, we analytically derive the dispersion relations for these collective modes in the long-wavelength limit. Notably, kinetic theory also incorporates collisionless damping effects known as Landau damping. We find that the branch cut structure responsible for Landau damping differs from the massless case: Whereas the massless system features only two branch points, the massive system exhibits an infinite number of such points forming a continuous branch cut.

We compute the $q\overline{q}g$ contribution to the diffractive structure functions in high-energy deep inelastic scattering. The obtained result corresponds to a finite part of the next-to-leading-order contribution to the diffractive cross section. Previous phenomenological applications have included this contribution only in the high-$Q^2$ or high-$M_X^2$ limits in the case of a soft gluon, and we numerically demonstrate that these existing estimates do not provide a good approximation for the full $q\overline{q}g$ contribution. Furthermore, we demonstrate that in addition to the soft gluon contribution, there is an equally important soft quark contribution to the diffractive structure functions at high $Q^2$.

The real-time correlators of quantum field theories can be directly probed through new approaches to simulation, such as quantum computing and tensor networks. This provides a new framework for computing scattering observables in lattice formulations of strongly interacting theories, such as lattice quantum chromodynamics. In this paper, we prove that the proposal of real-time estimators of scattering observables is universally applicable to all scattering observables of gapped quantum field theories. All finite-volume errors are exponentially suppressed, and the rate of this suppression is controlled by the regulator considered, namely, a displacement of the spectrum of the theory into the complex plane. A partial restoration of Lorentz symmetry by averaging over different boosts gives an additional suppression of finite volume errors. Our results also apply to the simulation of wave packet scattering, where a similar averaging is performed to construct the wave packets that regulate the finite volume effects. This result represents a necessary key step toward determining a broad class of scattering observables via quantum computing that are currently inaccessible via classical computing. Such observables are relevant for various applications, including hadron spectroscopy, hadron structure, and precision tests of the Standard Model. We also comment on potential applications of our results to traditional computational schemes.

Observations of astrophysical binaries may reveal departures from pure Keplerian orbits due to environmental influences, modifications to the underlying gravitational dynamics, or signatures of new physics. In this work, we develop a unified framework to systematically study such perturbations in the ambit of the perturbed Kepler problem and explore their impact on eccentric orbital dynamics and gravitational wave emission. Unlike traditional parametrized frameworks such as post-Newtonian and post-Einsteinian expansions, our approach offers a more source-specific modeling strategy, making it more natural to trace the physical origins of eccentric binary model parameters. Starting from a general perturbed potential, we derive the modified orbit and compute the associated gravitational fluxes and phase evolution, assessing their observational relevance for both current and future detectors. This framework thus offers a general and physically transparent toolkit for probing such subtle deviations from standard dynamics in gravitational wave data.

We analyze a cosmological solution to the field equations of a modified gravity model where curvature and matter are nonminimally coupled. The current Universe’s accelerated expansion is driven by a cosmological constant while the impact of the nonminimal coupling on the expansion history is recast as an effective equation of state for evolving dark energy. The model is analyzed under a tracking solution that follows the minimum of the effective potential for a scalar field that captures the modified theory’s effects. We determine the conditions for the existence of this minimum and for the validity of the tracking solution. Cosmological constraints on the parameters of the model are obtained by resorting to recent outcomes of data from the DESI Collaboration in combination with the $\mathrm{Pantheon}+$ and Dark Energy Survey supernovae compilations, which give compatible results that point to the presence of a dynamical behavior for dark energy. The gravity model violates the equivalence principle since it gives rise to a fifth force that implies the Earth and Moon fall differently towards the Sun. The cosmological constraints are intersected with limits resulting from a test of the equivalence principle in the Earth-Moon system based on lunar laser ranging data. We find that a variety of model parameters are consistent with both of these constraints, all while producing a dynamical evolution of dark energy with similarities to that found in recent DESI results.

The combination of independent cosmological datasets is a route toward precision and accurate inference of the cosmological parameters if these observations are not contaminated by systematic effects. However, the presence of unknown systematics present in different datasets can lead to a biased inference of the cosmological parameters. In this work, we test the consistency of the two independent tracers of the low-redshift cosmic expansion, namely the supernovae dataset from Pantheon+ and the BAO dataset from DESI DR2 using the distance duality relation which is a cornerstone relation in cosmology under the framework of general relativity. We find that these datasets violate the distance duality relation and show a signature of redshift evolution, hinting toward unaccounted physical effects or observational artifacts. Coincidentally this effect mimics a redshift evolving dark energy scenario when supernovae dataset and DESI datasets are combined without accounting for this inconsistency. Accounting for this effect in the likelihood refutes the previous claim of evidence of noncosmological constant as dark energy model from DESI DR2, and shows a result consistent with cosmological constant with $w_0=-0.92\pm 0.08$ and $w_a=-0.49_{-0.36}^{+0.33}$. This is further supported by an increased Bayes factor at the value of the dark energy equation-of-state (EoS) for cosmological constant ($w_0=-1$, $w_a=0$) when the distance duality inconsistency is accounted for. This indicates that the current conclusion from DESI DR2 in combination with $\mathrm{Pantheon}+$ is likely due to the combination of two inconsistent datasets resulting in precise but inaccurate inference of cosmological parameters. In the future, tests of this kind for the consistency between different cosmological datasets will be essential for robust inference of cosmological parameters and for deciphering unaccounted physical effects or observational artifacts from supernovae and BAO datasets.

We present a systematic analysis of Bell nonlocality and entanglement in ${\chi }_{cJ}(J=0,1,2)$ decays into a baryon pair ($B\overline{B}$), with particular emphasis on their production via the process $e^{+}{e}^{-}\to \psi (2S)\to \gamma {\chi }_{cJ}$ at BESIII. From the baryon-antibaryon spin density matrix, we construct measurable Bell observables and concurrence, revealing a striking hierarchy of quantum correlations: ${\chi }_{c0}$ decays exhibit maximal violation and entanglement; ${\chi }_{c1}$ decays violate Bell inequalities for ${\theta }_1\in (0,\pi )$ with angle-modulated strength; we find that the $B\overline{B}$ pair in ${\chi }_{c2}$ decays is in a separable state, and no indication of Bell inequality violation is observed. We provide complete analytical results for $J=0$, 1 and quantitative, uncertainty-aware estimations for $J=2$ based on experimental inputs from BESIII. These results establish the ${\chi }_{cJ}$ system produced via this radiative transition as a novel and promising platform for testing quantum entanglement and Bell nonlocality in high-energy collisions.

We propose a minimal extension of the Standard Model by introducing a Lorentz invariance violation (LIV) term into the $Z$ boson’s dispersion relation, expressed as $p_{\mu }{p}^{\mu }=M_Z^2+{\delta }_{\mathrm{LIV}}(p_{\mu }{n}^{\mu }{)}^2$, where ${\delta }_{\mathrm{LIV}}$ defines the violation scale and $n^{\mu }$ is a unit Lorentz vector specifying the direction of the violation. This perturbative modification alters the $Z$ boson propagator and decay rate, impacting the Drell-Yan process cross section at high-energy colliders. Observable effects are most pronounced near the resonance region at high rapidities ($|Y|>4$), potentially shifting the perceived $Z$ boson mass in general LIV cases and inducing additional sidereal-time modulations for spacelike and lightlike LIV due to the Earth’s rotation relative to distant stars. We outline a targeted search strategy for ATLAS and CMS, achieving sensitivity to LIV signatures down to $|{\delta }_{\mathrm{LIV}}|\approx {10}^{-8}$ (or even ${10}^{-9}$ in an optimistic scenario), offering a fresh perspective on historical and future collider data. Our model predicts that, in experiments with higher collision energies (and thus greater rapidities), the conventionally reconstructed weak boson mass exhibits a systematic shift. This could be particularly intriguing in the historical context of Tevatron and LHC weak boson mass measurements, where the discrepancy in $W$ mass measurements aligns with our LIV scenario.

Guided by the flipping principle, we propose a novel extension of the Standard Model based on a double right-handed $U(1)$ gauge symmetry. In this framework, all left-handed fermions are neutral, while right-handed fermions of the third generation carry charges distinct from those of the first two generations. This structure provides an explanation for the observed Standard Model fermion mass hierarchy; the heavy masses of the third generation are generated at tree level, while the lighter masses of the first and second generations arise radiatively at the one-loop level. For the active neutrino sector, the tiny masses are generated through a combination of tree-level and two-loop seesaw mechanisms. Crucially, this approach successfully reproduces the observed neutrino mass hierarchy, with the atmospheric mass-squared difference generated at tree level and the solar neutrino mass squared difference emerging at the two-loop level. These hierarchical patterns stem from the interplay between gauge invariance and a residual parity symmetry that survives the spontaneous breaking of the extended gauge group. The same residual symmetry stabilizes a viable scalar singlet dark matter candidate, which we show can reproduce the observed relic abundance while remaining consistent with current direct detection bounds. After addressing constraints from electroweak precision tests and flavor-changing neutral currents, we explore the discovery prospects for the new neutral bosons at existing and future colliders, including the LEP, LHC, and a future ILC.

We study axionlike particles (ALPs) in beam dump experiments, focusing on the Search for Hidden Particles (SHiP, at CERN) experiment and the Beam Dump eXperiment (BDX, at JLab). Many existing projections for sensitivity to ALPs in beam dump experiments have focused on production from either the primary proton/electron beam, or—in the case of SHiP—the secondary (high-energy) photons produced by neutral meson decays (e.g., ${\pi }^0\to \gamma \gamma$). In this work, we study the subsequent production of axions from the full electromagnetic shower in the target, finding order-of-magnitude enhancements in the visible decay yields across a wide range of axion masses. We update SHiP’s sensitivity curve and provide new projections for BDX. Both experiments will be able to reach currently unexplored regions of ALP parameter space.